In WP2 market replications will be set up through field pilots in Denmark, Greece, the Netherlands and the USA. Replications will be tailor-made to the local conditions, serving the needs of the local clients, decision makers and other stakeholders. Participatory technology assessments (pTA) with the SWS stakeholder groups will make clear whether SWS provide desirable answers to the local and regional societal and economic challenges. pTAs will be executed in WP3, as part of the SWS Knowledge Base.
The Marielyst area on the southern part of Falster Island is developed partly on land reclaimed in the nineteenth century, mainly for agriculture and recreational purposes (summer housing). The area is facing saltwater intrusion problems both from the sea and fossil marine waters in the deeper part of the exploited (confined) fractured chalk aquifer. Saltwater intrusion occurs due to drainage pumping and abstractions for water supply and irrigation (especially during summer), and is expected to increase further due to climate change and sea level rise.
In an ongoing study, initial assessments have been made on the potentials of SWS to control saltwater intrusion and to reduce risks of flooding from drainage canals, and eutrophication of coastal waters of the Baltic Sea around the Island. Potentially, the injection of treated water from the drainage canals into the underlying confined chalk aquifer may mitigate not only saltwater intrusion but may also reduce flooding and eutrophication risks. The latter is a severe problem for the ecological status of the Baltic Sea and many other coastal areas globally and techniques to reduce nutrient loadings from agriculture and sewage systems is currently evaluated in a large research program for the Baltic Sea in the Soils2Sea project.
SWS market replications at Falter Island will demonstrate the ability of SWS to control saltwater intrusion and reduce flooding and eutrophication risks. This shows the flexibility of SWS, being adaptive to the local environment and able to solve multiple water resources / quality issues in an integrative way. Moreover, the Falster Island replication allows for testing of SWS in a hydrogeological setting (fractured chalk aquifer) for which SWS have not been validated before.
The coastal site of the Schinias Natural Park is situated in the plain of Marathon, a typical Mediterranean environment that hosts important naturally occurring ecosystems (coastal wetlands, sand dunes and a pine forest), but also accommodates greenhouses, requiring high quality water. The multi-layer aquifer system consists of an upper unconsolidated formation of (mostly) fluvial sediments, surrounded and underlain by karstic marbles. Saltwater intrusion is a major issue in the upper aquifer housing the wetland/forest and agricultural activities, while the lower karstic aquifer has significant water flow that discharges directly to the sea.
The aim of the Schinias replication is to test SWS configurations that make use of water from karstic aquifers, adequately treated through novel pollution remediation techniques for the pumped water, including Reverse Osmosis (RO) coupled with Advanced Oxidation Methods (Ozonation/alternative AOPs), in order to ensure the recharge of the upper aquifer with high quality water. Both treatment techniques and recharge operations will be remote monitored and operated, so as to be applicable in similar remote locations.
Key elements of the Schinias replication are:
Demonstration of how a currently unused water source (potentially polluted groundwater and surface water) can be turned into a source for protection, regeneration and financial sustainability for the area (and other similar ones throughout the Mediterranean). This will show the strength of the integrative approach of SWS, solving multiple water resources issues. Schinias will be the second SWS application in fractured hardrock, after the Falster replication.
Dinteloord, the Netherlands, is a 3 km2 greenhouse horticulture area under development, with a predicted high water demand which cannot be fully supplied by precipitation in dry years. To meet the water demands, treated wastewater from a nearby sugar factory (sugar beets) is to be stored in a shallow brackish sandy (unconsolidated) aquifer, and recovered in dry years for irrigation. A pilot cycle including injection, storage, and recovery is planned to start in Autumn 2014, financed by the Dutch Topsector Water. The Dinteloord market replication allows for demonstration of the use of extensively treated wastewater for ASR and up-scaling of the Nootdorp/Westland reference pilots to large-scale facilities.
Specific characteristics of the Dinteloord replication, which feed the SWS Knowledge Base and Toolkit include:
Embedment of this pilot in SUBSOL allows us to continue operation and monitoring after the first ASR cycle (2015 onwards) and thus prolonged testing the ASR efficiency under varying hydrological conditions. We can thus validate the long-term applicability of the Dinteloord replication, and build trust with the local end-users.
The running ASR-Coastal reference pilots Nootdorp/Westland are both small to medium sized. Modeling studies have shown that the efficiency of ASR-Coastal systems may increase even further when applied at larger scale, with larger volumes of fresh water injected and temporarily stored. The Dinteloord replication allows for first time field testing of large-scale ASR-Coastal facilities.
The current ASR-Coastal reference sites use harvested rainwater for ASR. Dinteloord will use extensively treated (industrial) wastewater. This will be a third “new” water source tested in a SWS market replication, after agricultural drainage water at Falster Island and (potentially) polluted groundwater and surface water at Schinias. Through these and the Dinteloord replication, we will set further steps of integrating novel treatment technologies and SWS.
The Dinteloord replication is the first to reuse industrial wastewater for (in this case) irrigation purposes. This market replication thus adds to the SPIRE-PPP objective to accelerate water resource efficiency in the process industry, by making cross-links between agriculture and industry. pTA sessions will support the cross linkage process through scenario development , discussions, and trust building.
Maneadero Valley is a 35 km² coastal alluvial plain in Baja California, Mexico, producing high value crops such as tomatoes and cucumbers for local and export markets. Food production is under pressure because of a shortage of freshwater for irrigation. Overpumping of the aquifer has induced a strong intrusion of saltwater from the coast into the central valley. Because of this increasing salinization of the groundwater, already 1000 hectares of agricultural land have been taken out of production.
Farmers and (water) authorities are urgently looking for solutions to sustain freshwater supply, food production and thus the economy of the valley. In 2009, the Baja California State Government built a 20 km pipeline to distribute municipal reuse water from the city of Ensenada to the south of Maneadero Valley. Farmers, however, are hesitant to using this water, as they are concerned about the microbiological risks when irrigating (food) crops with reuse water. Also, the current (aboveground) storage capacity for this water is limited. Despite its substantial availability, reuse water in the valley is only used to irrigate 100 ha in an ongoing field pilot.
In 2014-2015, a SWS quick scan has been performed by ARCADIS and KWR, together with Mexican partners and stakeholders in Maneadero Valley. Together, they have drafted a potential SWS solution for the valley: (1) storage of large volumes of reuse water in the saline subsurface, (2) thereby creating a barrier against further saltwater intrusion, securing the freshwater wells land inwards, and (3) removal of pathogens from the reuse water by soil aquifer passage to secure microbiological safe irrigation water. All partners (including water authority COTAS, farmers, and the water and wastewater facility CESPE) are dedicated to upgrade the current reuse pilot to an SWS pilot in 2017 – 2018. An infiltration basin for the reuse water has already been constructed. For the pilot, permits are required for drilling and testing of a brackish water well (to promote freshwater infiltration in the saline aquifer, cf. Freshmaker) and for disposal of the brackish water. Drilling, testing and disposal permits are issued by CONAGUA.
Specific tasks in the Maneadero Valley market replication to which SUBSOL contributes, include:
- Development of a detailed hydrological model to evaluate SWS applicability and design in the Maneadero coastal alluvial aquifer. The model will be used for a more thorough SWS feasibility check, and will be validated and developed using hydrological and geophysical data already obtained by CICESE institute (Ensenada, Mexico). The model will be an important tool for the analysis of SWS designs and implementation studies in similar systems elsewhere.
- Maneadero SWS feasibility study, in which combined expertise from Mexico and Europe will be used to evaluate SWS potential to abate salinization and increase reuse water usage for crop irrigation in Maneadero Valley. This feasibility study will include evaluation of the local hydrogeology, regulatory framework, risks and cost-benefit analyses, and the design for SWS field pilot.
- Buildup of a SWS stakeholder group in Maneadero Valley to ensure acceptability of SWS technology and lower the barrier for market uptake. This stakeholder group will be consulted in the commercialization, capacity building and knowledge sharing activities.
- Development of a road map for full scale implementation of SWS at Maneadero Valley, including hydrotechnical and regulatory aspects.
Embedment of this pilot in SUBSOL will allow for knowledge exchange across the Atlantic, and will support SUBSOL partners with the buildup of a portfolio outside Europe, in a different hydrogeological, market and societal context. This may provide a stepping stone to other regions along the Gulf of Mexico that experience salinization problems.